Digital clocks may obtain different shapes and ways of displaying time. But what is a purpose of building purely digital clock? One of them probably for standing out in the crowd. Not everyone can tell the time by looking ad digital binary values and this makes you look geeky. Another reason is simplicity. Microcontrollers operate with binary values so displaying them is as easy as connecting LEDs to pins. Hawing this in mind Floating Wombat build really simple looking digital clock that uses only four RGB LEDs.
He wanted to make really simple front-face and so ended up with single pushbutton and four LED holes. Obviously he used different colors to tell hours, minutes and seconds. The clock runs on PIC24F16KA102 microcontroller that has internal RTC. 3 AA batteries ensure there is enough voltage for MCU and LEDs. Unique design of box enclosure definitely makes you think what it does… No surprise it is called Obfuscating Chronoscope.